This invention relates to flow regulating valves and apparatuses using such flow regulating valves. In the conventional needle valve regulators, flow of the fluid can be adjusted only by adjusting the gap between the needle and the conically formed valve seat, so that the fine and accurate adjustment is very difficult with such valves, and this kind of valve is not suitable especially for regulating speed of the piston of fluid driven machines and devices, because the flow rate of the fluid is limited appreciably by the small bore size of the conical valve seat.
Accordingly, one object of the present invention is to provide flow regulating valves, in which a fine and accurate adjustment of the flow rate is attainable over a wide range with a comparatively simple construction. Another object of the present invention is to provide flow regulating valves capable of controlling the flow of one direction and permit rapid flow of the opposite direction by using check valves together. Such flow regulating valves are usable for operating pistons of fluid driven machines and devices. Further object of the invention is to provide a fluid feeding apparatus which will feed the fluid for a predetermined time interval, using such flow regulating valves. Such apparatus may be used, for instance, for releasing a vacuum chuck rapidly, as well as for cleaning articles automatically, etc.